


I'm the Thing that Lurks in the Darkness

by Bananapuddle



Category: Adventure Time, Kuroshitsuji | Black Butler
Genre: Action/Adventure, Demons, F/F, F/M, Fun, Vampires
Language: English
Status: Completed
Published: 2014-10-13
Updated: 2014-10-13
Packaged: 2018-02-21 01:08:52
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,719
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2449724
Author URL: https://archiveofourown.org/users/Bananapuddle/pseuds/Bananapuddle
Summary: <blockquote class="userstuff">
              <p>Marceline is forced to deal with an angry demon that just missed his last meal and has set foot in The Land of Ooo.</p>
            </blockquote>





	I'm the Thing that Lurks in the Darkness

"Why do you want me to do it? Can't you just ask Finn  Jake? You know they'd love to slay a demon!" I yell.

"You know very well that you will be the best for the job and they are going to be to buzy guarding the Gumball Ball tomorrow." The princess sneers. I sigh I actually don't mind the job that much I just can't stand the fact that she only calls me when she needs something like this. I take a step forward. Our faces are so close that she appears to only have one eye.

"Well then," I pause and smile."Will I be your plus one?" I slide my face down the side of her neck placing light kisses on her pink skin.

"Marceline..." Princess bubblegum warns, but her voice is shaky and I don't stop. Her sweet bubble gum scent filling up my nostrils. "You know why we can't do this." That's when I stop kissing her neck and bite her smooth flesh taking a big chunk of bubble in my mouth. "Marceline!" She screams clutching her throat. I laugh blowing a huge bubble in her face before I disappear and leave her to her duties.

She's so annoying. Why can't she just be straightforward about how she feels about me and not say all this _"you know why we can't do this."_ crap. I obviously don't know why. If you like someone and they like you back, you date them simple as that. We used to date, but it only changed because of her. My feelings have stayed the same. I float up to the tree house I used to live in. I shudder remembering my dumb ex boyfriend, and how dumb I’d been to try and make her jealous of that loser. I float in front of the window and watch as Finn and Jake make breakfast.

"Bacon pancakes making bacon pancakes. Take some bacon and I put it in a pancake. Bacon pancake thats what its gonna make bacon cakesss." I'm unnoticed by the house occupants and easily slip in. I quickly slide into the fridge positioning myself in between the milk and orange juice. The cold doesn't bother me, in fact it only adds to my hunger to laugh at the pranks I play on people. "Yo dude what do you want to drink?” Jake says as footsteps near the fridge. I bite my lip to keep from giggling at the anticipation of his terror. Just as he opens that refrigerator door I jump out spreading my jaw wide allowing him to have a perfect view of my sharp teeth and snake like tongue. _AHHHHHHHHH_ he screams and trips backwards as I throw my head back in laughter.

“Truly that never gets old.” I float over to the table where Finn sits and I pull out a chair to sit across from him. Jake scuttles in the kitchen throwing me an annoyed look but it only makes me laugh more. “So Finn, how would you like to slay a demon?” Finn looks down at his pancakes.

“Uh sorry Marcilene but PB told us not to…” His cheeks turn a light pink just like the shade of her skin. My hands clench in to fist at my sides as I begin to rise out of the chair. “Marceline…” My lips frown and my vision begins to go fuzzy. “Marceline!” I let out a low growl. Why does everyone have to chose her over me? I crash through the window and soar all the way back to the safety of my cave. The door is unlocked and I waltz in straight to my closet. It takes a while but I finally find what I’m looking for then I grab my gray sweatshirt with a red cat on it. Even though I don’t get cold I love the feeling of an oversized sweat shirt covering my body.

When I arrive in the Ice Kingdom I’m welcomed by Gunter. I gather him into my arms and smile down at him. I carry him all the way up the steps to the ice castle and knock twice then enter finding Simon with his head in the book I got him: _She’s Just Not that Into You_. He smiles when he sees me.

“Oh Marcy! Have you brought me something or do you want to just talk about hot princess?” I roll my eyes, but allow a smile to creep onto my face. I should feel bad about using Simon this way but until he remembers who he is he’ll always be this gullible nuts old man.

“Both.” I say, walking towards the throne he sits in. Taking his cold hand in mine I place a small vile of purple liquid on his palm.

“What the stuff is this?”

“It’s a potion that will turn you invisible for 15 minutes. I don’t need it because I have the power to do so as I please. And as for the princess part you will be using this to kidnap Princess Bubblegum.” An evil grin folds onto my lips as I tell him exactly what to do.

About 30 minutes later I’m sitting in a tree watching as the invisible man takes PB from her tidy bedroom. I snicker and disappear heading back for home ready for a nice long sleep.

I wake up to my phone vibrating on my dresser. Blinking away the sleep I read the contact agreeing that if it was anyone else I would be planning a very big inconvenience for them right now.

“Get here now.” The princess says then hangs up. I don’t know why I do what she says but there was something in her voice that tells me not to mess with her right now. I put on my high waisted pants along with my floppy sun hat and yellow gloves. When I’m outside I immediately feel they scrapping feeling of the sun attempting to melt my skin but I just ignore and make my way over to the Candy Kingdom.

She’s in the lab which is safe from the sun's rays and I remove my gloves and hat placing them on a table near the door. The princess is learning over a still body of one her candy people. I’m startled when she looks up at me tear stained. I want to go over and pull her into my arms placing light pecks on her head. But I don’t.

“What's wrong?” None of my emotion shows through my face.

“The demon has stolen the souls of five of my candy people. Marceline why couldn't you have killed him before…” She sighs wiping her eyes.”I’m sorry I shouldn’t blame you. It’s just as much my fault by allowing myself to be kidnapped by Ice King.” My cheeks burn the very color I love to eat. She squints at me as I try to regain my composure but it’s too late. “HOW COULD YOU?”

“I’m sorry, Bubblegum, I’m so sorry.” I try to grab her arm but she moves to the side.

“GUARDS!” The banana guards scuttle into the room. “Make sure I never see her in the Candy Kingdom again.” Her anger radiating off her face enough for her not to even need to change it into something as terrifying as mine.

“But….” She turns away and before the guards are near me I grab my hat and gloves and fly out of the room and far away from the Candy Kingdom.

Oh frick. This is not good. Well atleast I know how she feels about me. I’m floating over an empty field feeling both the pain from the princess hating me and the sun. I can’t decide if I should try to make it up to her by getting rid of this demon or just wait till she gets over it. That's when a thought comes to me. I fall down landing on my feet, my eyes are wide. If there is a demon lose in Ooo not only the candy people are at risk but the Princess herself and everyone else who lives her. _Crap_. I rack my brain for whom this demon might go for next. All the kills we know of have been low level and just as sweet as the candy they're made out of. The demon will probably go for something more filling but who? Whose soul would I devour if I were fully a demon? And not a moment later I am soaring towards the most innocent and pure soul in Ooo. I’m flying towards my past residence, the tree house.

“FINN!” I yell! I fly to the window but there is no one in the darkened kitchen. Ahhhhhhhhhh I hear a garbled scream from somewhere in the house. Crashing through their newly repaired window I lose my hat but I can’t go back for it now. I jump down the hole where the latter is. At the bottom I spot Jake curled up on the floor, all of his limbs are tied together in a series of crazy knots. Finn’s body is pressed up against the wall and a tall slender figure his holding him there. The figure is dressed in a long black old fashioned coat covering his white dress shirt and black pants. He turns to me, his jet black bangs fall across his face and his deep red eyes pierce my own.

“Demon.” I say through gritted teeth.

“Halfling.” He slurs. He lets Finn fall to the floor then all of a sudden he’s in front of me. Finn groans letting me know he hasn’t lost his soul yet.

“You say that as though its a bad thing.” I smirk, knowing I have more powers than this demon can ever imagine. A sinister grin spreads across his lips which makes my heart skip a beat. Before I know it he’s over to the window opening it wide allowing a ton of light to pour on to my skin. I scream as my skin withers under the light. He slowly closes the window. _Damn demon_. He strides back over to Finn. “Put him down.” My skin slowly starts to heal itself and I take mental note to kick his ass extra hard. He turns to me eyes a wild fire.

“I’m sorry to disappoint you but I will not be putting him down. I have just lost the most delicious soul in all eternity and I will not starve myself any longer.” I push him off Finn and to the other side of the wall.

“Yeah well find your meal elsewhere.” He pushes off the wall and we go flying across the room landing on a wooden table breaking it as my back hits the floor with a crack. He leans forward placing his lips next to my ear.

“It’s rude to interrupt someone’s lunch like that. How would you like it if I stole your precious shades of red?” I spin around pinning him to the earth. I straddle him grabbing his shoulders pulling them up and bring them back down banging his head against the cold ground.”Because I know you don’t know anything about your stronger demon side or anything about the cuisine of souls.” He pushes up against my hands to a sitting position.

“Well obviously I know something about it because I came here!” I spit then remember I’m still straddling him and jump up to floating two feet off the ground. He stands up slowly. “Well are you going to fight!?”

“I never desired to fight the vampire queen, but I guess if that’s what it takes to have a decent meal then I will do what I must.” The demon pulls his arm up in front of his face and I notice a purple pentagram tattooed into it but before I can dwell on it he whips out four knives between his finger nails and fling them at me. I doge all of them.

“Is that the best you got?” I taunt and this time when he throws them one slices my cheek. It’s not a bad feeling. “I’m honestly tired of playing. Let me see your true form.” Another grin splits his face.

“That would be wildly inappropriate being that there are mortals here.”I frown even though he is probably right.

“Fine. We can fight elsewhere.” As soon as the words leave my mouth he's grabbed me pressing me against his chest and we are soaring upwards straight through the roof of the tree house. His embrace shields my sun sensitive skin. He looks down at me.

“You better start flying now because in case you weren't aware demons can’t fly.” I squeeze my eyes shut and begin the hard labour of keep his body and mine afloat. Soon we land at the entrance of my house inside the safety of the dark cave I call home. I’m a little tired from carrying him but it doesn’t stop what I’m going to do next. I push him through my open door straight into one of my wooden chairs. I move a long rope from my closet into my hand and in a blur wrap it around his chest securing him to the chair.I step back and smile.

“Hmmm what should I do with you? I could kill you or send you back to the Nightosphere. Either option would make the princess happy.” The thought tugs on my heart a little. Would the princess be happy? Would she be happy enough to love me again?

“Or I can show you the powers that you’ve neglected from your demon half.” His smile is charming but irksome.

“If I really wanted to gain those powers I would talk to my dad.”

“But you won’t. You hate your dad.” I hate to admit it but I’m startled. “Oh please, even if it weren’t for the fact that you never visit him, your a teenage girl and what teenage girl does not hate her daddy?” I want to slap him but instead I pull a chair around to face him. “You know if you untie me we can have a more personal conversation.”

“Tell me about the mark on you hand.” His whole body stiffens. When he doesn’t say anything I get up and reach my hand into his breast pocket pulling out one his knives. I’m surprised to find it’s something I can find in a kitchen, but it will do. I place it on the fleshy part of his pale cheek then press down and drag it across his face to the edge of his eye. Ruby red balls roll down like tears but he doesn’t flench. I bend down and lick the red away enjoying it’s warmness in my stomach. I sit back in the seat across from him and stare into his crimson eyes desperately wanting to snack on that seductive color.

“You must truly know nothing about demons. This is the mark created by a contract with a human. It allows demons to mold someone into the perfect soul by helping it extract it’s revenge.”

“So where is this human your contracted to? Why don’t you eat them instead of trying to chow down on my friends.” Allow chuckle escapes his lips.

“Those are your friends? I’d expect better from the vampire queen.” He tsks. “ Well the thing is, my master is no longer living he was turned into a demon before I could devour his soul. It’s really quite complicated actually.”

“But if you didn’t eat his soul doesn’t that mean you still have a contract with him?”

“Ah, yes that’s where it’s complicated. Someone would say yes but that wouldn’t be fair  would it? When I found out I ran. I ran as far and as fast as I could. Can you imagine after all those years of preparing a meal it it was all of sudden being taken away from you.” His eyes are alive with anger and I pity anyone who is at the other end of all that rage. “He's here you know. I did not eat the souls of those candy people he did.” I shudder at the thought of two demons in Ooo.

“Nope. No. No. You are going right back to the Nightosphere right now.”

“I can help you get rid of the other demon.” Do I want his help? I just want the princess to be happy. But thats dumb. If she can’t be happy with me then why do I care so much?

“What’s your name?” My breath catches in my throat as he breaks the ropes and stands so close to me that our chest touch. I move back bumping into my dining room table and he takes a step forward pushing our bodies together. He’s taller and bends over slightly to place his lips next to my ear.

“You didn’t actually think those ropes could hold me did you?” He pauses then says: “Sebastian Michaelis.” His lips hover directly above mine. My eyes grow wide and he smirks moving his face away from mine. “ Well it looks like we have the same problem: Ciel Phantomhive.”

“So you want to kill him?” I let out a breath still recovering from his closeness. Sebastian is attractive and the worst part about is he knows it.

“If it comes to that maybe but all we need to do is remove his eye and send him back to the Nightosphere. He is not strong enough to open the portal on his own so you wont have to worry about him back in Ooo again.”

“Why his eye?” Sebastian points to the symbol on his hand. “Thats on his eye! Thats kind of cool I guess. Where will we find… Ciel?”

“Well since he has been eating candy people… is there any place where a lot of the hangout.”  My lower lip drops. “What?”

“The mother frickin Gumball Ball.”

“Well we should go then.”

“No. I can’t. The Princess kicked me out.” I look down at my red boots. He laughs and grasps my chin lifting my face up to meet red orbs.

“We’ll then I guess we have to crash this party.” I smile and put all worry of what PB will think out of my mind. I turn towards my room. “Where are you going?”  
“What you’re wearing maybe acceptable to wear to the ball but the princess would definitely kick my ass if I wore this.” I close the door to my room and let the smirk stay on my face. My life hasn’t been this interesting for a while. Quickly stripping down to my underwear I throw open my closet to find the only dress I own. Its purple and strapless. I slip it on over my head then grab my bass axe preparing to battle the demon Ciel. I exit the room to find Sebastian waiting at the door. He smiles at me and takes my hand as we walk towards the candy kingdom. Night has fallen and I feel energized. Sebastian keeps looking at me as we walk and it starts to bother me.

“What?”

“I was just wondering who you had originally planned to go to this ball with. And don't say something like _nobody likes me_ because we both know that people can’t resist the darkness.” I don’t look at him.

“Princess Bubblegum.”

“A female?” I turn to him, my cheeks heating in annoyance.

“Do you have a problem with that?”

“No. I was just surprised you were into that.”

“Well I’m into a lot of things.” We walk in silence until I can see the front gate into the candy kingdom.

“Is she the one that kicked you out?”

“Yes."

“Well this should be interesting.” So in one hand I clutch my bass and in the other a demon I just met earlier today and together we enter unseen into the building where ball is held.The first thing I notice is all the color its almost sickening how bright it is. All colors of the rainbow. There a few round tables in the corner and some rectangular ones with all kinds of tarts and treats on them. Most people were on the floor doing some sort of waltz to the sound of the candy orchestra playing some classical tune.

“Hey look its Marceline!” _Oh dirt_ , its Finn if he sees Sebastian it will be very bad. Sebastian realizes this too and pulls me on to the dance floor and begins to lead me in a waltz.

“I… I’m not very good at dancing.”

“Well then I guess it’s very fortunate that I’m an excellent at it.” He smiles placing his arm around my waist and spinning me around. I look around to see if Finn is still calling me but instead my eyes lock with Princess Bubblegum’s. “Is that her?” I nod my head yes. He smiles as he presses his lips to mine. Out of the coner of my eye I see PB frown and stomp away and his mile is transferred to my lips. I can feel him chuckle as he parts his lips causing me to do the same. He tastes like a rich shade of red that can only be described as dark chocolate. I love the way his wet mouth feels around my pink tongue. He breaks the kiss pulling his lips to my ear. “It’s really not polite to show this type of affection in public. But I’d be more than willing to finish this in private.” My cheeks heat up again and even though I enjoyed that kiss I’m not sure if I want the demon D.

“Sebastian.” The word is whispered but Sebastian still snaps his head around to see the owner of the voice. I glance over his shoulder meeting eyes with a boy with multi colored eyes. One is purple with the same pattern on Sebastian's hand on it. I quickly unstrap my bass from my axe and before the boy has anytime to react I slam it down against his purple eye. He screeches, but it is unheard over the loud classical music. My whole body is thrown to the side by Sebastian. My side collides with ground and I struggle to my feet. Sebastian nears the boy. I crouch down low jumping towards the blue headed boy with my axe ready to make another blow. My eyes widen as Sebastian steps in front of Ciel and throws a series of of his knives at me, each one lodging its way into my skin. I can’t help but feel betrayed. Sebastian turns toward Ciel. My hands begin to clench into fist again and I can feel my anger rise like bile in my throat.

“Ciel I would never let them hurt you.” Ciel looks so hopeful and innocent when he looks up at Sebastian. I can feel a transformation coming on me. Sebastian clasps Ciel’s little chin his hands and begins stroking the boys plump cheeks with his thumb. He stops at the crook of his nose and lifts his thumb to press into Ciel’s purple eye. There’s a distinct popping sound and another scream from the boy. “Marcilene open the door to the Nightosphere now!” Ignoring my anger I bend down to draw a happy face on the floor. Then I reach into my pocket to retrieve a bottle of  bug milk and pour it over the face.

“Maloso vobiscum et cum spiritum!" I chant as the ground opens up exposing the darkness of the Nightosphere. By now all the candy people have realized what is happening and begin running about causing chaos I have to push a few out of the way so the won't fall into the Nightosphere.

"Marcilene!" I feel a warm hand on my shoulder. "What are you doing! Your ruining the ball! And I told you never to come back here!" Spits PB over all the screaming and music. I turn around to face her.

"Really are you gonna do this now? I'm doing what you told me! I'm getting rid of the demon that has been terrorizing your candy people!" Out of the corner of my eye I watch as Ciel begins to transform into his true form.

"You are weak! I expected more from you Sebastian." His nails grow into large talons which he sticks in Sebatains gut and throws the demon against the wall. Their is an empty socket where Ciel's eye should be. His face contorts from an innocent boy to something black and scaley. His mouth unhinges showing many rows of jagged sharp teeth. Huge black bat wing explode form his back and and a long scorpian's tail grows from his behind pointing directly at me. He lets out a loud growl as he brings the tail down right where I am standing. I jump out of the away bringing PB with me her face is slicked with sweat and she stares terrified at the monster infront of us. I look around to see a shocked Finn and Jake.

"Get the candy people out of here!" I scream. They begin clearing the room. The monster has his tail stuck in the ground is desperately moving about to get it out. "You need to leave too." I tell the princess she nods her head and runs towards the door. The room is nearly cleared and the monster is almost free again. I run to the other side of the room to where Sebastian. "What are you doing?! Why aren't you fighting him?"

"He's the only thing I can't fight." He says as a loud scream is heard from the otherside of the room. I turn to see PB clutched in one of Ciel's large claws.

"PRINCESSS!" I sprint forward jumping and once I'm into the air I transform into a large snarling wolf. I pounce on the demon and he lets PB fall to the floor. We crash to the ground rolling across the floor to the edge of the entrance to the Nightosphere. I open my wolf like jaw and chomp down on his neck hearing his outersketleton snap under my bite. He groans but I under estimate him and he barrels his tail straight into my shoulder I let out a scream. Both wounded we begin to change back to our human forms and I try to ignore the shoting pain his stinger is causing my shoulder. I pull the little boy up and pull him close to my face. His eyes drop down ward with sleep. "Don't forget your place! Your a young and weak demon! You should think better of trying to fight the vampire queen." I bring my arm back and throw the sack of limps down into the entrance of the Nightosphere. The entrance begins the close causing the earth to shake. I fall to my knees clutching my shoulder. I watch silently as PB runs toward me. "Princess Bubblegum... I'm sorry." I feel my self being lifted up and just before my eye close I hear PB scream no.

When I wake up I'm lying on my bed. I throw my legs over the side and stand up. I'm wearing my black no smoking shirt and blue shorts. I stride into my living room.

"I could just about kill you!" I yell flying over and pinning Sebatain against my blue couch. He smirks.

"What fun would that be?" His smile is contagious and I find myself doing the same. I sit up straddling him and I pull his hand up to my face.

“It's gone.” The purple pentagram is no longer etched on the back of his palm.

“It is.” Sebastian sits up and wraps his arm around my body. “All thanks to you I can live rest of eternity without Ciel Phantomhive.”

“Do you miss him?”

“Only the delicious smell of his soul.”

“No I mean do you miss _him?”_ I look into the dark yummy red eyes.

“Yes. Maybe I will seek out his company again but it has to be on my own terms not because of some silly contract.”

“So what are you going to do now?” Sebastian’s stomach begins to growl.

“I going to find another soul to eat.”

**Author's Note:**

> Thanks for reading this :) I hope you enjoyed it and I'd love any comments or feed back.


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